Refrigerating apparatus



March 7, 1944. A, A, MCCRMACK 2,343,514

REFRIGERATVING APPARATUS Fi1ed March 14, 1941 v 3 Sheets-Sheet 1 im@ E) -rfrllll/lli l k March 7, 1944. A. A. MCCORMACK REFRIGERATING APPARATUS 3 Sheets-.Sheet 2 Filed Marh 14, 1941 IN ENTOR,

A. A. MCCORMACK REFRIGERATING APPARATUS March 7, 1944.

Filed March 14, 1941 l 5 sheets-sheet :5

Md INVENTOR I MW ma 7" Patented Mar. 7,

'REFRIGERATINGAPPARATUS Alex A. McCormack, Dayton, Ohio, assignor to General Motors Corp oration, Dayton, Ohio, a

corporation of Delaware Application March 14, 1941, Serial No. 383,381 i 14 Claims. This invention relates to refrigerating apparatus" and more particularly to an' improved rel frigerating system of the reverse cycle type for use in air conditioning.

It has long been known that a refrigerating system may be used for either heating or cooling the air for an enclosure by reversing the cycle of operation in some manner or the other. A large number of arrangements have been proposed for reversing the cycle of operation of refrigerating systems but none have gone into extensive use either because of the complicated controls which have been required or because of other difllculties.

One object of. this invention is to provide ai5 simplified reverse cycle system in which all of the refrigerant controls are mounted wholly within the sealed refrigerant circuit.

Another object is to'provide a system iii which the cycle of operation' may be .reversed merely by reversing the direction of rotation of the compressor.-

|An other object of this invention is to provide an improved and simplified means for-controlling the iiow of condenser cooling water which may also be used for controlling the iiow ofwater over the evaporator during the heating cycle.

A further object of this invention is to provide an improved oil sump arrangement in which the main supply of'lubricant is subjected to the high side pressure at all times irrespective of the direction of rotation of the compressor.

A further object of this invention is to provide an improved means for separating the lubricant from the compressed refrigerant.

A further object of thisinvention is to provide an improved rotary compressor especially adapted for use in -a reverse/.cycle system. g

' Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

Inthe drawings:

Fig. 1 is a vertical sectional Iilg. 2 is a sectional 2-2 of Fig. 1:

Fig. 3 is al sectional view taken on the line 3 3 of Fig. 1; t

Fig. 4 is a fragmentary sectional .viewtaken on the line I-I of Fig. 3;

Fig. -is a diagrammatic system embodying my invention; and

l view showing the motor-compressor construction;

view taken on the lineI Fig. 6 is an enlarged sectional view showing one of the refrigerant valves.

Referring now to the drawings, reference character I0 designates a sealed unit which functions as a motor-compressor-condenser unit during the cooling cycle and functions as a motor-compresser-evaporator unit during the heating cycle. The fan `unit I5 circulates air to be conditioned in thermal exchange relationship with a heat exchange unit II arranged in refrigerant flow relationship with Qsthe unit I0. The iow of refrigerant between the units I0 and II is controlled by a xed restrictor diagrammatically shown at I3. The fixed restrictor maybe of anyconventional construction such as aV small bore capillary tube. 'I'he unit I0 comprises an upper shell I2 within which is mounted a motor "Il, having a iield winding I6 and an armature I8. The motor I4 shown herein is merely intended to represent a conventional motor of the type which may be caused to operate in either direction desired. Electrical energy is supplied to the motor through the leads 20.

A finned water con. zz is mounted within thev casing I2 between the motor stator and the lower portion of the. casing I2 as shown in the drawings. Water enters the coil 22 through the inlet 24 and leaves the coil through the outlet 26. During the cooling cycle the water flowing through the coil 22 serves to condense the compressed refrigerant discharged from the compressor and during the heating cycle the water gives up heat to the low pressure liquid refrigerant supplied to the unit III from the heat exchange unit I I. The coil 22 is held lnplace by means of one or more bolts such as the bolt 28. Spacer washers are provided on each of the bolts 28 so as to hold the various convolutions of the coilj22 in proper spaced relationship. As shown in the drawings,v

the bolt 28 is provided with an elongated head 32 which serves to spacethe lowermost convolut tions'of the coil 22 from the ring 34. As shown' in Fig. 1, the coil 22 is provided with fins such las 23 so as to increase the heat transfer surface of the coil. The motor stator I6 is supported byv 1 the main frame 38 which also includes a bearing extension 38 within which is journalled the main `motorcompressor shaft 40. The frame 33 is view of a reverse cycle bolted or otherwise secured to the casing 44 which encloses the main compressor mechanism and which serves as a lubricant reservoir. The casing Il is `provided with a ange 42 to which the rihig and the main frame 33 are secured as s wn.

The compressor comprises a conventional fourv vane rotor 48 operated by the shaft 4l in the usual and well-known manner. During thecooling cycleI refrigerant vaporized in the heat exchange coil ii leaves the coil Il through the line 68 and enters the compressor through the port 50. The compressed refrigerant discharges from the compressor through the port 52 as best shown in Figs. 2 and 4. Lubricant is supplied to the motor-compressor bearing through the central bore 54 provided in the main shaft 48. In order to avoid the necessity for a mechanical lubricant pump, I make use of the difference in pressure between the suction side and the discharge side of the compressor for forcibly feeding lubricant to the bearing surfaces in the manner explained more fully hereinafter. Since the direction of rotation of the compressor is reversed when the cycle of operation of the refrigerating system is reversed, it is necessary to provide some means for maintaining the pressure within the lubricant supply chamber substantially equal to the high side pressure irrespective of the direction of rotation of the compressor. It isalso desirable to provide some means for returning to the lubricant sump that lubricant which is discharged from the compressor along with the compressed gas. In order to maintain the pressure within the lubricant chamber 44 substantially equal to the high side pressure at all times. I have provided a pair of pressure operated valves 58 and 88 which tend to equalize the pressure between the lubricant chamber 44 and the high side of the refrigerant system. Valve 58 is arranged. in the passage 56 provided in the main frame 36 and valve 68 is arranged in the passage 64 which connects the lubricant chamber with the refrigerant line 65. Thef'passages 5I and i4 also serve as return passages for the lubricant discharged by the compressor.

Since a certain amount of lubricant is at all times discharged from the compressor along with the 4compressed gas, it is desirable to provide some means for separating the lubricant from the compressed gas. As shown in Fig. 4, the 85S and lubricant discharged by the compressor through the port 52 is required to flow through a. porous sintered bronze plate i3. In passing through the 4porous' bronze plate 53. the lubricant separates from the refrigerant and drains into the lowermost portion of the motor housing with the result that upon opening of valve 58 the lubricant returns to the lubricant sump 44. Upon 1 reversal of the direction of rotation of the compressor, the port Il serves as the discharge port. In order to separate the lubricant from the refrigerant discharged through the port il, I have provided a second porous sintered bronze element 55 which serves to collect the lubricant adjacent the inlet to the valve 88' whereby upon opening 'of the valve 88 the lubricant returns to the main main compression ,chamber lubricant sump 44. In order to insure the continuous return of lubricant to the main lubricant sump, I have'provided a small capillary tube Il which has its one end opening into the -lubricant chamber above the lubricant level therein and its other end .communicating with the interior of the compression chamber 82. Since the one end of the tube is open to the high side pressure and the other end is open to the compression chamber 82, at a point where the pressure therein is very nearly equal to the low side pressure. enough refrigerant vapor will dow from the l' lubricant chamber into the compression chamber to make room for the lubricant returning to the lubricant sump. The size of the capillary tube ing water in response not only serve to return 'flows upwardly through the passage 54 in the shaft 40 and is fed to the bearing surface through one or more passages such as 18 shown in Fig. 1. The passage 18 feeds the lubricant to the groove provided in the shaft 40 at the upper end of the bearing 38. The high pressure lubricant is prevented from escaping from the upper end of the bearing by means of a shaft seal 8i which may be of any conventional construction. The seal 8| also prevents high pressure gas from the motor compartment from interfering with proper lubrication of the upper end of the bearing. A lubricant return passage 1t)l is provided which has its lower end communicating with the compressor chamber 62 at a point midway between the inlet and outlet parts whereby the pressure at the outlet of the passage is very nearly equal to the low side pressure regardless of direction of rotation. By virtue of this arrangement, the lubricantwhich is under high pressure at 88 is caused to flow along the shaft bearing and into the groove 12 which communicates with the passage 10. A certain amount of lubricant will also nd its way to the groove 12 from the main compression chamber whereby the entire upper bearing is lubricated. The lower bearing is also lubricated in much the same manner. Thus a lubricant return passage 14 is provided which corresponds to the passage 10 whereby lubricant under high pressure in the and in the lubricant sump 44 finds its way along the lower bearing into the groove 16 which communicates with the passage 14.

The new of water through the con z2 is controlled bythe pressure operated valve SII which varies the flow of water in accordance with the variations in the pressure within the lubricant sump 44. Line 82 connects the sump 44 with thevalve 90. The valve S'is of the type now used extensively for controlling the ow of coolto variations in head pressure and needs no further description.

By virtue of the above described arrangement. the valves 58 and 68 serve a triple purpose. They the lubricant discharged from the compressor to the lubricant sump, but also serve to maintain the lubricant sump under high pressure irrespective of direction of rotation of the compressor. Two distinct advantages result from maintaining the lubricant sump under pressure. In the iirstplace, it provides forced lubrication and in the second place, the pressure within 'i the lubricant chamber may be used in controlling the flow of w ater through the coil 22 during both cycles of operation.

Itwill also be noted that each of the porous sintered bronze elements 53 and 55 serves a dual purpose. Thus each element serves as a lter for the suction gas a portion of the time and as an oil separator for the discharge gas another porwhich refrigerant may flow in either of two directions, a first heat exchange unit, a second heat 'exchange unit, refrigerant compressing mechanism, refrigerant flow connections between said heat exchange units and said compressing niechanism, means forming a lubricant sump from which lubricant is supplied to said compressing mechanism, means for so driving the compressing mechanism as to cause ow of-refrigerant in either direction through saidsystem, means for maintaining lubricantin said sump at a pressure substantially equal to the pressure at the discharge side of said compressor, means for restricting. the ow of refrigerant from one of said heat exchange units to the other of said heat exchange units, means for flowing air to be conditioned over one of said heat exchange units,

means for flowing an extraneous medium in thermal exchange with refrigerant in the other of said heat exchangel units and means responsive to the pressure within said lubricantsump controlling the flow of said extraneous medium.

2. Refrigerating apparatus comprising in combination, a first heat exchanger, a second heat exchanger, a rotary compressor, refrigerant ow connections between said heat exchangers and said compressor, means for operating said compressor to cause flow of refrigerant in either of two directions, said refrigerant flow connections including a lubricant sump, means for supplying lubricant from said sump to said compressor, and means for maintaining the lubricant in said sump at a pressure higher than the compressor suction pressure irrespective of the direction of rotation of said compressor.

y3. In combination,l a rst heat exchange unit,

a second llieat exchange unit, means for flowing air to be conditioned in thermal exchange with one of said units, means for circulating an ex traneous medium in thermal exchange with the other of said units, compressor mechanism, refrigerant flow connections between said heat exchange units and said compressor mechanism, means for so ldriving the compressor mechanism as to cause flow of refrigerant in either ofl two directions through/said compressor and said heat exchange units, means for maintaining one portion of said refrigerant flow connections under condensing means, a lubricant sump within said casing, means for maintaining said lubricant sump at a pressure substantially equal to the pressure at the outlet of s'aid compressor, and a bleeder port between said lubricant sump and the compression chamber of said compressor, said bleeder vport terminating above the liquid level .in said sump, said motor including'means for reversing the direction oi rotationof said compressor.

6. In combination, a casing, partition means within said casing, a compressor within said casing, said compressor having an outlet on one side of said partition means and a lubricant supply sump lon the other side of said partition means, means for supplying lubricant from said sump to said compressor, an opening in said partition means for returning lubricant from said compressor outlet to said sump. a valve for said opening, means for withdrawing refrigerant vapor from said lubricant sump into said compressor, and a porous metal plate adjacent the outlet of said compressorfor sepa-rating the lubricant from the refrigerant.

7. In combination, a reversible compressor having a pair of ports adapted to serve as inlet and outlet ports, a lubricant sump for said compressor, means for supplying lubricant from said sump to =said compressor, a first passage leadingfrom one of said ports to said lubricant sump, a second 4' passage leading from another of said ports to said sump, and means cooperating with said passages for maintaining said lubricant in said sump at a pressure of said compressor.

, 8. In combination, a reversible compressor having a pair of ports adapted to serve as inlet and outlet ports, a lubricant sump for said compressor, means for supplying lubricant from said sump high side pressure irrespective of the direction of flow of refrigerant through said heat exchange units; and means responsive to the pressure in said one portion controlling the flow of said extraneous medium. l

4. In combination, a casing, means forming a plurality of -chamberswithin said casing, a rotary compressor within said casing, inlet and to said compressor, aiflrst passage leading'from one of said ports to vs'aid'lubrican't sumpa second passage leading l'ron'i another of said ports to said sump, means cooperating with said passages for maintaining said lubricant vin said sump at' a pressure substantially equal to the discharge pressure of said compressor, and oil separating,

means adjacent each of said ports.

9. In a refrigerating system, a casing, a wall member dividing said casing into a motor com'- partment and a compressor compartment, a bearing in' said wall member, a shaft -jpurnalled in said bearing, a motor in said motor compartment foi` rotating said shaft, a compressor withvin said compressor compartment driven by said grshaft, said compressor comprising an inlet port outlet ports for said compressor, means for driving said compressor including means for reversing the direction of rotation of said compressor whereby the inlet and outlet ports are interchanged in function, one of said ports communicating with one of said chambers and the other of said ports communicating with another of said' chambers,means for supplying lubricant to said compressor, porous sintered bronze filter elements provided for each of said ports adapted to separate lubricant from the refrigerant dis-v ocharged by said compresson and means for returning the lubricant thus separated to the means for'supplying lubricant to saidv compressor.

5. In combination, a casing, refrigerant con- I f densing means within said casing, a motor with- Y in.V said casing. a rotary compressor within said casing, arefrigerant evaporator in refrigerant communicating withl said motor compartment and an outlet port communicating with said compressor compartment, a body of lubricant within said compressor compartment, means utilizing the diierence in pressure between said compressor compartment and said motor compartment for supplying lubricant tosaid bearing,

. and means for preventing the escape of lubrimechanism, refrigerant li'low connections .be-v

cant from said bearing into said motor compartment. y

10. In a refrigeratng System, a iirst heat ex'- change unit, a second heat exchange unit, means for flowing a. fluid to be treated in thermal ex change with oneof said units, means for circulating an' extraneous medium in.the rmal exchange with the other of said units, compressor tween said heat exchange units and said com- I pressor mechanism, means' for so-'driving the flow relationship with saidcompressor and said compressormechanism-as to causeno'w oi'- refrigf erant in either of two directions to reverse the functions of said heat exchange units, means for maintaining one portion of said refrigerant flow connections under high side pressure at ali times when said compressor mechanism is in operation, and means responsive to the pressure in said one portion controlling the ow of said extraneous medium.

1l'. In combination, a casing, means forming a pluralityof chambers within said casing, a rotary compressor within said casing, inlet and outlet ports for said compressor,I means for so driving the compressor as to cause ow of refrigerant in either of two directions whereby the inlet and outlet ports are interchanged in funct n, one of said ports communicating with one o said chambers and the other of said ports cornmunicating with another of said chambers', means for supplying lubricant to said compressor, porous sintered filter elements provided'for one of said ports adapted to separate lubricant from the refrigerant discharged by said compressor, and means for returning the lubricant thus separated to the means for supplying lubricant to said compressor.

12. In combination, a reversible compressor having a pair of ports adapted to serve as inlet and outlet ports, a lubricant sump for said compressor, means for supplying lubricant from said sump to said compressor, rst passagemeans from one of said ports to said lubricant sump, second passage means from another of said ports to said sump, and means cooperating with said passage means for maintaining said lubricant in said sump at a pressure substantially equal to the discharge pressure of said compressor irrespective of direction of rotation of said compressor.

13. In combination, a casing. partition means within said casing, a compressor within said casing, said compressor having an outlet on one side of said partition means and a lubricant supply sump on the other side of said partition means, means for supplying lubricant from said sump to said compressor, a by-pass opening in said partition means for returning lubricant directly from said compressor outlet to said sump, a valve for said opening, and means for withdrawing refrigerant v'apor from said lubricant sump into said compressor.

14. In combination, a casing, a rotary compressor within said casing, inlet and outlet ports for said compressor, means for so drivingi the compressor as to cause flow of refrigerant in either of two directions whereby the inlet and outlet ports are interchanged in function, means for supplying lubricant to said compressor, porous sintered filter elements provided for one of said ports adapted to separate lubricant from the refrigerant discharged by said compressor, and means for returning the lubricant thus separated to the means for supplying lubricant to said compl'eSSOl. 

